You should be able to use your current wireless router to basically boost the signal from the other network.  It’s called a network bridge.

If your router doesn’t support it, you can get one wireless adapter that is made for like a console and plugs into an ethernet port, and have the ethernet cable go into your router and then have your Xbox and PC go into your router.

I’m moving in with a buddy and we both have wireless routers.
How can I connect my desktop and XBox to the current wireless network w/o having to purchase separate wireless adapters/cards for both? Is there a way to use my current router to connect to the the current wireless network and then connect the PC and XBox to the router?
Or is a wireless bridge/hub(not sure which is correct) the way I should go?
My desktop only has a wired ethernet card running XP.

Thanks.

I forgot to mention that the existing router is in one side of the house while my room(where I’ll put my deskto/xbox) will be on the other. I am well aware of the switch capability on the router but in order for me to do that I’d need to have a long cable that I’d rather not have running from one side of the the house to the other.

i think theres a way to do that but i dont know how. if you had like 20 bucks you could ebay a wireless g-card, sell your router and use that money. then share the connection, wire from your pc to the xbox. but im sure theres a better way.